Imaging the atomic-scale electronic states induced by a pair of hole dopants in Ca2CuO2Cl2 Mott insulator

TL;DR

This study uses scanning tunneling microscopy to visualize how pairs of hole dopants affect the atomic-scale electronic states in a cuprate Mott insulator, revealing new insights into doping effects.

Contribution

It provides the first atomic-scale visualization of electronic state evolution induced by dopant pairs in Ca2CuO2Cl2, a parent cuprate insulator.

Findings

Spectral weight transfer creates a broad peak and V-shaped gap.

Peak position drops sharply at ~4 Å distance.

In-gap states depend on dopant configuration.

Abstract

We use scanning tunneling microscopy to visualize the atomic-scale electronic states induced by a pair of hole dopants in Ca2CuO2Cl2 parent Mott insulator of cuprates. We find that when the two dopants approach each other, the transfer of spectral weight from high energy Hubbard band to low energy in-gap state creates a broad peak and nearly V-shaped gap around the Fermi level. The peak position shows a sudden drop at distance around 4 a0 and then remains almost constant. The in-gap states exhibit peculiar spatial distributions depending on the configuration of the two dopants relative to the underlying Cu lattice. These results shed important new lights on the evolution of low energy electronic states when a few holes are doped into parent cuprates.